Is the computed time

ABSTRACT

JOB IS THEN ADDED TO THE JOBS BEING PERFORMED BY THE SYSTEM. IF THE ELAPSED TIME IS LESS THAN A MINIMUM, THEN THE JOB WITH THE EARLIEST PROMOTION TIME IS DEMOTED FROM THE JOBS BEING PERFORMED.   A VIRTUAL MEMORY SYSTEM INCLUDES A MAIN MEMORY WHICH ACCOMMODATES SEVERAL JOBS ON A TIME SHARED BASIS. WHEN A JOB REQUIRES DATA NOT IN THE MAIN MEMORY, SECONDARY MEMORY IS ACCESSED BY MEANS OF A SIGNAL KNOWN AS A PAGE FAULT. A LIST (STACK) OF PAGE FAULTS AND THEIR REAL TIMES IS RECORDED. AT THE TIME OF EACH FAULT, THE ELAPSED TIME FOR A FULL STACK OF FAULTS IS CALCULATED AND TESTED TO FIND WHETHER IT EXCEEDS A MAXIMUM. IF SO, A NEW

DEFENSIVE PUBLICATION UNITED STATES PATENT AND TRADEMARK OFFICEPublished at the request oi the applicant or owner in accordance withthe Notice of Dec. 16, 1969, 869 O.G. 687. The abstracts of DefensirePuiwlicaiion applications are identified by distinctly numberedscriesand are arranged chronologically. The heading of each abstractindicates the number of page; of specification, including claims andsheets of drawings contained in the application as originally filed. Thefiles of these applications are available to the public for inspectionand reproduction may be purchased or 30 cents a sheet.

Defensive Publication applications have not been examined as to themerits of alleged invention. The Patent and Trademark Oflice makes noassertion 21s to the novelty of the disclosed subject matter.

PUBLISHED NOVEMBER 4, 1975 Pitt mm {A Elli A virtual memory systemincludes a main memory which accommodates several jobs on a time sharedbasis. When a job requires data not in the main memory, secondary memoryis accessed by means of a signal known as a page fault. A list (stack)of page faults and their real times is recorded. At the time of eachfault, the elapsed time for a full stack of faults is calculated andtested to find Whether it exceeds a maximum. If so, a new job is thenadded to the jobs being performed by the system. If the elapsed time isless than a minimum, then the job with the earliest promotion time isdemoted from the jobs being performed.

NOV. 4, 1975 D. D. CHAMBERLIN et a1. T940,017

RESOURCE BALANCING SYSTEM FOR MULTIPROGRAMMING SYSTEMS WITH A VIRTUALMEMORY AND PACING ALLDCATION Original Filed March 13, 1974 PAGE TAuLT IREAD REAL TIME /II HAS THE FAULT STACK REACHED 12 FULL SIZE (SYSTEMsTARTuP) YES PUT THE CURRENT REAL PUT THE CURRENT REAL TIME ON THE TIMEON THE STACK STACK AND DELETE THE EARLIEST TTHE I ON THE STACK. COMPUTETHE ELAPSEO EXIT TIME BETWEEN THE EARLIEST AND LATEST FAuLTs ON THESTACK.

/15 IS THE COMPUTER T|ME THRE5HOLD1(MAXI? NO YES COMPUTED TIME INITIATEPROMOTION ROUTINE I6 THRESHOLD 2mm)? IHo YES I EXIT EXIT SCAN THE MP8FOR THE JOB WITH THE EARLIEST PROMOTION TIME.

INITIATE THE DEMOTION x18 ROUTINE FOR THIS JOB.

EXIT

